The present invention relates to the art of migrating volumes among storage subsystems, including a technology for migrating a volume of a primary storage apparatus or secondary storage apparatus in a remote copy system having the primary storage apparatus and secondary storage apparatus, to another storage apparatus.
Along with the advancement of IT and the spreading of the Internet, the amount of data stored in computer systems of enterprises and the like is continuing to increase, and storage subsystems storing such data are required to have greater capacity and higher performance. Therefore, when a storage subsystem is used for a given number of years, it is replaced with a new-generation system.
In principle, the computer systems used in enterprises and the like are required to realize non-stop operation, and the storage subsystems are also required to operate in such manner. Therefore, downtime must be suppressed to a minimum during replacement of storage subsystems. For example, Japanese Patent Application Laid-Open Publication No. 2007-115221 (Patent Literature 1) relates to migrating volumes from a migration source storage A to a migration destination storage B. Patent Literature 1 teaches migrating volume pairs subjected to volume mirroring within the storage subsystem or from a storage subsystem to another storage subsystem, and enabling to accept I/O requests during migration of volumes from the migration source subsystem to the migration destination subsystem.
Additional references include US Patent Application Publication No. 2005/0149577 (Patent Literature 2), U.S. Pat. No. 6,101,497 (Patent Literature 3), U.S. Pat. No. 5,742,792 (Patent Literature 4), and U.S. Pat. No. 7,152,079 (Patent Literature 5).
There is known a remote copy system with a primary storage apparatus (PDKC) and secondary storage apparatus (SDKC), wherein data is copied from a primary logical volume (PVOL) of the PDKC to a secondary logical volume (SVOL) of the SDKC. Remote copying is categorized into synchronous remote copying whereby, in synchronization with writing data into the PVOL, the data is written to the SVOL, and asynchronous remote copying whereby, asynchronously with writing data into the PVOL, the data is written into the SVOL. For example, Japanese Patent Application Publication No. 2005-182222 (Patent Literature 6) discloses a technology concerning synchronous remote copying for migrating a PVOL to another storage apparatus.
According to the technology disclosed in Patent Literature 6, a virtual management network needs to be installed in the remote copy system and a migration-source PDKC needs to provide a function for migrating a PVOL. The situation for migrating a PVOL can be considered one wherein the PVOL is migrated using a storage apparatus of the old model that manages a currently operated PVOL to be synchronously remote-copied as a migration source, and a storage apparatus of the new type that is newly installed as a migration destination. In this situation, according to the technology described, the migration-source PDKC might not necessarily be capable of migrating the PVOL, although it needs to be. Making the migration-source PDKC capable of migrating the PVOL can be cumbersome. In some cases it is even impossible to make the migration-source PDKC capable of migrating a PVOL. The problem described above applies to a case where an SVOL is migrated from a migration-source SDKC to a migration-destination SDKC.